Condenser system for railway cars



June 21, 1938. J. GQBERGDOLLQ CONDENSER SYSTEM FOR RAILWAY CARS I Filed March 6, 1935 2 Sheets-rSheec 1 m gg o 00 O0 0o 00 00 00 0o 00 00 OO Patented June 21,1938

CONDENSER SYSTEM FOR CARS John G. Bergdoll, York, Pa., assignor to York Ice Machinery Corporation, York, Pa., a corporation of Delaware Application March 6, 1935, Serial No. 9,680

1 in the means used to condense the refrigerant.

The invention has been developed particularly with reference to conditioning air in passenger cars and certain problems inherent in such in- 1 stallations will be discussed, but broadly considered, the invention is applicable to refrigeration systems used on cars and other vehicles, regardless of the purpose to which the refrigeration 'is applied.

Refrigerative conditioning plants as applied to railway cars are in operation only when atmospheric temperatures are relatively-high. There is no location on the exterior of the car at which condenser cooling air at low temperature is avail"- able, and as a practical matter location of the condenser beneath the car body is virtually necessary. In such a location the condenser is subject to heat radiated from the road bed, and in the path of air which has derived heat from the locomotive or other propelling units.

The use of air cooled condensers is desirable because it is impracticable to carry in the car suihcient water for water cooling unless cooling towers are used. Space for cooling towers is not conveniently available, and even if available the wide ranges. of temperature encountered on long trips, and the conditions developed by entrance of cinders and dirt, introduce serious maintetion of such a condensing system to railway cars.

Important features of novelty are the delivery of humidifying water by pressure derived from the air brake system, and control of water delivery by head pressure (in the condenser) or equivalent means, .so that water will be used only when conditions are such as to require it. As refinements of the invention means are shown to assist the air flow over the condenser by the motion of the car. As the direction of motion of railway cars is frequently reversed, it is nec- 6 Claims. (01. 257-25) essary, where air circulating fans are used, to reverse the fans in response to reversal of motion of the car, and in some cases also to deliver, the water selectively to different .humidifying nozzles. Such arrangements will be described as embodied in modifications.

In the drawings:--

Fig. l is a side elevation of a passenger car with the invention applied, showing the preferred location of the condensers and water storage tank.

Fig. 2 is a perspective view showing the brake pipe, water storage system and refrigeration circuit.

Fig. 3 is an elevation of one of the condenser units, as viewed in Fig. 1.

Fig. 4 is a section on the line flt of Fig. 3.

Fig. 5 is a section similar to Fig. 4 showing a modification of the condenser.

Fig. 6 is a similar view of another modification.

Fig. 'I is a detail view of a device used with the structure of Fig. 6 to select the nozzles.

The embodiment shown in Figs. 1 to i wiliflrst be described.

A passenger car body of conventional form is illustrated at it and is supported on trucks it (Fig.1). .Hung beneath body it in the'interval 1 between the trucks it are all the components of the refrigerating system shown in Fig. 2, except the evaporator and related components of the conditioning unit. Those units which are indicated in Fig. 1 are the water storage tank it. two condensers it and conditioning unit it (which includes the evaporatonand also related parts not concerned with the present invention and hence not illustrated, such as circulating fans and the like).

Referring to. Fig. 2 a multl-cylinder air cooled compressor is indicated at It. No driving means is shown and any known in the art may be used, such as mechanical drive from an axle of, a truck it, or electrical drive using current from any source such as a battery charged by an axle-'- driven generator, the latter being the usual commercial practice.

The compressor it discharges through line ll, iii and branches It to two condensers, indicated generally by numerals I l. The use of a plurality of condensers is commonly dictated by space considerations and any suitable number, one or more, may be used as circumstances render advisable. From condensers H branch liquid lines, 2! lead to liquid line 22 which delivers refrigerant to receiver 23, having a charging and purge con nection 24 and sight glasses 25.

lid

.From the receiver 23 line 26 leads through strainer 21 to the expansion valve 28, which delivers refrigerant through pipe 29 to an evaporator, not illustrated in detail, but forming an essential part of the conditioning unit IS. The discharge header of the evaporator is indicated in dotted lines at 3| andis connected to the suction line 32 which leads to the suction connection 33 of the compressor l6 through a strainer 34.

Expansion valve 28 is preferably of the automatic type and may be of any suitable construction. In Fig. 2 is shown a thermostatic bulb 38 connected by tube 35 with the body of valve 28 to exercise control in response to the temperature of evaporator discharge. It is to be understood that the valve includes some control in response to evaporator pressure. No novelty is here claimed for the expansion valve.

A high pressure cut-out 36 connected by branch 31 with discharge 'line H is provided to shut down compressor l6 if discharge pressure rises above a safe working limit. This limit is higher than the pressure at which the automatic water control valve, hereinafter described, is set to operate.

The brake pipe forming part of an air brake system is shown at 38. This may be any brake pipe under suitable air pressure. In the usual automatic systems used on passenger cars, the air pressure in the brake pipe is pounds gage under running conditions. Running pressures as low as 70 pounds gage are. however, used in some classes of. service. Leading from brake pipe 38 is a branch 38 which delivers air to a reducing valve 4|, set to charge a storage reservoir 42 to av lower pressure say 60 pounds gage, and hold such charge against reflux to the brake pipe despite reductions of brake pipe pressure made from time to time to produce brake applications.

A second reducing valve 43 delivers air from reservoir 42 to line 44 at a still lower pressure, say 20 pounds gage. Line 44 leads towater storage tank or reservoir l3 and thus places the water under a static head of 20 pounds gage.

A,dip pipe 45 delivers water through it normally open hand operated stop valve 46 and strainer 41 to a water regulating valve 48 which controls the supply of water through line 48 to the spray heads of condensers l4. The valve 48 is operated by a pressure motor 5| subject to pressure in pipe l8 through branch connection 52 and is so contrived that valve 46 will open and close as pressure in line 18 passes above and below a chosen value.

with one refrigerant commercially used in railway car conditioning this value has been satisfactorily set at approximately pounds gage, but the pressure is selected on the basis of economic head pressure limits and depends in part on the thermodynamic characteristics of the refrigerant to be condensed. The purpose of I the valve 'is to suspend humidification and conserve water when reasonable head pressures are attainable without humidification of the cooling air.

While valve 48 responds directly to head pressure, it responds indirectly to those atmospheric conditions which control head pressure under operating conditions. Broadly considered therefore the opening and closing movements of valve 48 are controlled by the physical condition of cooling air approaching the condensing unit or units,,and approximately equivalent results can be secured by means other than a controller responsive directly to head pressure, though this last is preferred.

The construction of the condensing units l4 can be best explained with reference to Figs. 3 and 4. A horizontal duct or housing made up of top plate 53, bottom plate 54 and side plates 55 is closed at one end by a grille or screen 56 and at the other end by a plate 51 having two circular apertures, in each of which is mounted a two-bladed air-circulating fan 58 driven by a corresponding electric motor 59. The air enters through the screen and is drawn through the duct by the fans which operate whenever compressor I6 is running.

The branches l9 deliver compressed refrigerant to a top header 6| in each condenser and the condensed refrigerant is collected by bottom headers 62, one ineach condenser and delivered to the branches 2| of the liquidline. Connected to and extending between headers GI and 52 are coils arranged in two groups spaced a short distance apart in the direction of air flow. The first group comprises a small number of coils 63 and the second group a larger number of coils 64.

Between the two groups and directed toward the first are atomizing nozzles 65 fed by supporting'stand pipes 66 which are connected to branches of water pipe 49. A nozzle is shown in front of each fan 58, so that they dischargesubstantially at the center of the air stream induced by each fan.

The capacity of the water nozzles 65 is small, only about two gallons per hour for each nozzle being required in a four nozzle installation as commercially used on a standard railway car. Air heated by coils 63 is cooled and humidified by the atomized water before contact with the coils 64. Neither set of coils is wet toany material extent as the spray evaporates almost entirely in suspension in the air. The beneficial effect of this comparatively insignificant quantity of water, used as described, is surprisingly great. In commercial installation on railway cars as mentioned above using Freon as a refrigerant, the effect under actual service conditions is to reduce head pressure in the condenser from about 200 pounds to 160 pounds gage. .The saving in power consumption, and the reduced wear on the compressor, are of peculiar importance in this class of service.

Since the coils are not drenched and since no water isrecirculated, the difficulties encountered .with cooling towers, because of scaling of coils drain the spray system as an incident to shut- .ting it down, so that freezing up in cold weather somewhat by causing the air flow to occur in harmony with the travel of the car, but in such case the fans must be reversed as an incident to reversal of direction of travel of the car, and in .some installations it may be desirable to cause different sets of nozzles to operate in different directions of car travel.

Figs; 5 and 6 show modifications illustrative of the principles involved.

In Fig. 5 the groups of coils 63a and 64:: are

. Gear 13b is fast to pulley body "b.

Shaft 'ii may be the car'axle, or the shaft of a reversible motor whose direction of rotation is reversed preferably automatically by reversals of car travel, so that the fan assists'the natural air flow.

In Fig. 6 a single group of coils 63b is used instead of two groups. Two spray nozzles 85b and Bio are used, one on either side of coil 63b and means, preferably automatic, are provided to deliver water to them selectively, so that only air approaching the coil is humidified.

.The fan 58b is driven by a belt from shaft lib which reverses as the car travels in reverse directions. As in the case of Fig. 5, shaft lib may be a car axle or a reversible motor. Between the pulley 12b and fan 58b is a bevel planetary train made up of two sun gears 13b and 14b and a'planet gear 15b mounted-to swing about the common axis of gears 13b and 14b.

to fan 58b.

The reversal of torque as. the drive reverses will cause displacement of planet gear 15b which is connected by link 16b to valve 11b in valve (See Fig. 7.) Shifting of valve ,IIb

connects water supply line 49b selectively tois 'merely typical "of .valve shifting means re-* sponsive to reversal of direction.

One important aspect of Fig. 6 should be particularly observed. Air approaching the condeningmeansoperatedbythe ser is heated, by the propelling unit and also by radiation of heat from the road bed as above explained, and hence is in condition to receive and quickly evaporate moisture. Thus it is in condition to receive considerable additional humiditv, and active evaporation of the spray occurs in advance of the'condenser coil "D.

The various embodiments above described are intended to be illustrative and not limiting.

What is claimed is:-

1. The combination of a vehicle having a brake pipe in which pneumatic pressure is developed; a water reservoir subiect to static pressure derived therefrom; a surface condenser;

meansfor passing air in heat exchanging relation with said condenser; and means for humidifying said air prior to contact with aportion of said condenser, comprising water spraywater. I 1

12b and gear 14b fast Btltld head on said 2. The combinationof ,a vehicle having a brake pipe in whichpneumatic pressure is developed; a water reservoir subject to static pressure derived'therefrom; a" surface condenser; means'for passing air in heat exchanging relation with said condenser; Lmeans for humiditying said air, prior to contact with a portion of said condenser, comprising water spraying means operated by the-static head on saidwater; and

means responsive to condenser pressure and controlling the delivery of such water alternately to cause and suspend humidification as condenser pressure passes above and below a chosen value.

3. The combination of a vehicle adapted to travel in relatively reverse directions; a source of water thereon; a condenser, in heat exchanging relation with which air is circulated in rela-' tively reverse directions as an incident to relatively reverse travels of the car; and means controlled by the direction of motion of they car for delivering moisture from said source to air approaching at least a part of said condenser to humidify the same.

4. The combination of a vehicle adapted to travel in relatively reverse directions; a source of water under pressure head carried by said vehicle; a surface condenser exposed to air flow induced at least in part by motion ofthe vehicle; a pair of spray devices, one for humidifying air passing over the condenser in each direction of motion of the vehicle; and means responsive to direction of motion of the vehicle for delivering water from said source to said spray devices selectively.

5. The combination of a vehicle adapted to travel in relatively reverse directions; a source of water \mder pressure head carried "by said vehicle; a surface condenser exposed to air flow induced at least in part by motion of the vehicle; and a pair of spray devices, one for humidifying air passing over the condenser in each direction of motion of the vehicle. T V

6. 'I'hecombination of a vehicle, including a pneumatic brake system and an air storage resmeans for spraying water under said pressure head into the last named air as the latter approaches at least a portion of said condenser,

and at a rate which will ensure evaporation of the water in the air without substantially wetting said .condenser.

' JOHN G. BIRGDOLL. 

